Fire Fighting is a very hazardous occupation. On average, there are 600,000 structure fires annually and 3.0 deaths per 100,000 structure fire. Alarmingly, this death toll has doubled since 1977. Most of the fatalities are a result of heart attack and asphyxiation, complicated by the fact that rescuers cannot locate a downed victim in time to provide aid. Unfortunately, there is no equipment available today that will provide a rescuer with the location of a downed or lost firefighter and directions on how to best reach the victim. Tiercent is working to develop a solution: a system that will track the path and location of firefighters inside burning structures and alert the accountability officer when an individual is in need of assistance. The system will graphically display the 3D path and location of the downed firefighter such that a rescue team can quickly lend assistance. Tirecent aims to reduce firefighter fatalities 50% by reducing the average time it takes to search for a downed or lost firefighter. The firm's commercialization plans aim to penetrate 30% of the emergency services market by 2006, delivering 2,500 systems to the marketplace. Upon completion of this Phase 1 Research Project, Tiercent will demonstrate the feasibility of a system that uses a unique combination of radio frequency and inertial based technologies to locate a person within a 50'x50'x50' dwelling. More specifically, the system will provide information on the floor that a person is on, as well as their location on this floor, within five feet of accuracy. There are three sets of experiments in the Phase I research plan; floor level determination, X-Y accuracy improvement, and algorithm validation. The results of these experiments will be signal processing algorithms to determine firefighter location using a single three-axis body-mounted accelerometer and a radio frequency location system. Algorithm validations will be performed by collecting accelerometer and radio frequency tracking data during routine firefighter training exercises. The research plan calls for the use of: 1) ten paid firefighters from Troy, NY, 2) a fire training facility in Rensselaer County, NY, 3) Wearable Accelerometric Motion Analysis Systems, developed by Stanford University, and 4) the Wherenet real-time location system.